With the advance of HDD technology and the accompanying increases in the areal density of stored information, the magnetic fields read by a magnetic-recording head from the recording surface of a magnetic-recording disk have become progressively smaller. Consequently, flying the magnetic-recording head closer to the magnetic-recording disk by reducing the fly height has become of greater concern. For example, the fly height of the magnetic-recording head in a HDD may be as low as a few nanometers (nm) with the use of thermal fly-height control (TFC). The close proximity of the magnetic-recording head to the magnetic-recording disk raises concerns about head-disk interactions (HDIs) that may be deleterious to HDD performance and reliability. Thus, engineers and scientists engaged in the development of HDDs are interested in providing a HDD environment of high reliability for the retrieval of information that has been stored at high areal density.